1. Field of the Invention
This invention relates to a container transfer lift which is used for lifting a container from a platform provided in front of a warehouse, or other building, onto a truck drawn up alongside it, or lowering the container from the truck.
The term "container" as herein used means a wheeled case or case-like structure in which a plurality of objects can be packaged together for transportation. It does not only mean a typical shipping case forming a single truck or rail-wagon load, but also covers other forms of structures, such as a bogie provided with an upstanding framework and a pallet provided with a wire net or fence defining its sidewall.
2. Description of the Prior Art
A platform which is often provided in front of a building, such as a warehouse, is higher than the ground level, but the bed of a truck, particularly a heavy one, is usually still higher. They do not form a plane surface when the truck is drawn up alongside the platform. Therefore, it has been usual to lay a plate in an inclined position between the platform and the bed of the truck for lifting a container from the platform onto the truck, or lowering it from the truck, along the inclined surface of the plate. Although this is a very simple method, the container which holds heavy objects is so heavy that the movement thereof up or down the inclined plate is a very hard work. This is particularly the case when the platform is narrow and no ample space is available between the truck and the building.
It has also been possible to use a power gate, crane, or other device provided on the truck. This method is, however, useful only when the truck is equipped with any such device.